This invention relates to an optical contact unit and an optical connector.
Referring to FIGS. 1 and 2, a conventional optical contact 1 comprises an optical fiber 2 and a ferrule 3 fitted onto an end portion of the optical fiber 2. The ferrule 3 generally comprises a ceramic cylinder 31 and a metal cylinder 36. The ferrule 3 is connected through the metal cylinder 36 to the end portion of the optical fiber 2.
Generally, an optical connector comprises a first optical contact holding member 8, a second optical contact holding member 9, and the optical contact 1 fitted into the first and the second optical contact holding members 8 and 9. The first optical contact holding member 8 has receiving holes 87 and 88 for receiving a top or forward end of the ferrule 3, which end is to be faced to a mating optical contact (not shown). Likewise, the second optical contact holding member 9 has a receiving hole 95 for receiving a rear end of the ferrule 3 and an optical contact fixing tube 10. The first and the second optical contact holding members 8 and 9 are fixedly coupled to each other by the use of any suitable coupling means. Alternatively, the first and the second contact holding members 8 and 9 may be formed in an integral shape.
The metal cylinder 36 of the optical contact 1 has a flange 36a. The flange 36a is provided with rotation preventing grooves 36b. The rotation preventing grooves 36b are engaged with rotation preventing protrusions 89 formed on the first optical contact holding member 8. By the engagement between the rotation preventing grooves 36b and the rotation preventing protrusions 89, the optical contact 1 is prevented from rotating about an optical axis thereof.
The optical contact 1 is fixed to the first and the second optical contact holding members 8 and 9 through the optical contact fixing tube 10 and a coil spring 11. The optical contact fixing tube 10 has an outer peripheral surface provided with an external thread 10a. At one end portion of the optical contact fixing tube 10, a stepped portion 10b is formed on an inner peripheral surface thereof. The coil spring 11 is fitted on the metal cylinder 36 of the optical contact 1. The coil spring 11 has one end brought into contact with the flange 36a of the metal cylinder 36 and the opposite end brought into contact with the stepped portion 10b of the optical contact fixing tube 10.
The external thread 10a of the optical contact fixing tube 10 is screwed into an internal thread 96 formed in the receiving hole 95 of the second optical contact holding member 9. Thus, the optical contact fixing tube 10 is fixed to the second optical contact holding member 9. Simultaneously, the coil spring 11 is put into a compressed state between the flange 36a and the stepped portion 10b. In this event, the coil spring 11 applies a pressure on the flange 36a. Due to the pressure, the metal cylinder 36 of the optical contact 1 is pressed against the first optical contact holding member 8. As a result, the optical contact 1 is fixedly arranged with respect to the first and the second optical contact holding members 8 and 9. Thus, the optical contact 1, the optical contact fixing tube 10, and the coil spring 11 are assembled together when the optical contact fixing tube 10 is threaded into the internal thread 96 and fixed to the second optical contact holding member 9 in the state that the optical contact 1 is fitted into the first and the second optical contact holding members 8 and 9.
As described above, the conventional optical contact is fixed to the first and the second optical contact holding members by the use of other separate components such as the optical contact fixing tube and the coil spring. In this connection, it is troublesome to fit the optical contact into the optical contact holding members. Because of the same reason, it is also troublesome to remove the optical contact from the optical contact holding members for examination and maintenance of the optical contact.
When a number of the optical contacts are arranged in the optical contact holding members, a relatively large pitch is required. This is because the conventional optical contacts are fixed to the optical contact holding members by the use of the separate components such as the optical contact fixing tube and the coil spring as described above. As a result, the optical contacts can not be arranged in the optical contact holding members at a high density.